What's your number, Kevin Mitnick?

Doing this, he said, would allow employees to verify a caller was who they said they were by calling them back at the provided number. In the case of someone looking to snaffle company details over the phone, it would scare them off immediately. If the caller was legitimate, they would be happy to comply with the request.

"If people would just call people back," Mitnick told attendees at a forum hosted by vendor Citrix this morning in Sydney, "it would eliminate 80 percent of the threat".

Mitnick described how the Motorola employee who delivered him secret company source code back in his hacking days gave him a nervous moment when the call was almost lost as she put him on hold to check some details with her security manager. Ultimately, however, that attempt succeeded.

While most people naturally wanted to help others who contacted them, he said, employees needed to be taught to deny requests that could compromise security.

The reformed hacker -- currently a security consultant -- pointed out those attempting to breach company security relied upon the intelligence-gathering they did in the lead-up to an attack. One fantastic target for such information, he said, was the company's IT helpdesk.

"They're there to help," he enthused, pointing out fraudsters calling a help desk number would be able to find out what verification tokens -- such as date of birth or employee ID number -- help desk staff used to verify a caller's identity. They could then go away, do some research and come back armed and ready to breach a user's account.

While Mitnick's social engineering tips are ultimately timeless and technology-neutral, the ex-hacker is obviously keeping up with today's tech gadgets.

He pointed out one of Apple's AirPort devices (a popular wireless hub) could instantly create a wireless access port into any company's headquarters if plugged into a company network port.

"You could just put a company logo on it, with a label saying 'IT Department, do not remove'," he said. "You could be browsing the network from the parking lot."

A USB bluetooth device would fulfil the same function if plugged into the back of an employee's PC, he said.